$A$ sphere of $30 \ cm$ radius is dropped into a cylindrical vessel of $80 \ cm$ diameter,which is partly filled with water. If its level rises by $x \ cm$,find $x$ (in $cm$). (in $.5$)

The area of a big rectangle is equal to the area of a small rectangle. If the length of the big rectangle is equal to the length of the small rectangle and the width of the big rectangle is $2 \ m$,what is the width of the small rectangle?

If the length of one diagonal of a rhombus is $80 \%$ of the length of the other diagonal,the area of the rhombus is how many times the square of the length of the longer diagonal?

In a swimming pool measuring $90\, m$ by $40\, m$,$150$ men take a dip. If the average displacement of water by a man is $8\, m^3$,what will be the rise in water level? (in $cm$)

Find the area of a triangle in which each side measures $8 \text{ cm}$ (in $\sqrt{3}$)? (in $\text{sq. cm.}$)

$A$ rectangular park is $65\, m$ long and $50\, m$ wide. Two cross paths,each $2\, m$ wide,are to be constructed parallel to the sides. If these paths pass through the centre of the rectangle and the cost of construction is ₹ $17.25$ per $m^2$,then find the total cost involved in the construction (in ₹).